posix_errno

Gives your Elixir programs access to your system's errno.h mappings, so they can

1. understand the exit statuses of spawned programs, and

2. use :erlang.halt/1 to tell other POSIX programs why Erlang died.

Usage

Interpreting exit codes:

import System.POSIX.Errno

too_many_args = "1234567890" |> List.duplicate(100_000)

{_, exit_code} = System.cmd("true", too_many_args)

IO.puts ["Process failed: ", errno(exit_code).description]
# => Process failed: Argument list too long

Emitting exit codes:

# something terrible has happened to a process we're doing IPC with!
errno(:EPIPE).code |> :erlang.halt

Installation

posix_errno is implemented as a NIF written in Rust, and therefore needs Rust to be available in the build environment. Use rustup to install.

Then, add posix_errno to your list of dependencies in mix.exs:

def deps do
  [{:posix_errno, "~> 0.1.0"}]
end